USGS IN YOUR STATE

USGS Water Science Centers are located in each state.

Duration Graphs

(Updated Bi-weekly)

Duration graphs characterize the state of the hydrology of a stream with respect to time. To quantify the state of the hydrology for the current year, the current daily mean flows, or running 7-day averages of flows are compared to selected non-exceedance percentiles computed for each day of the year over the history of the gaging station. In addition, 7-day minimum flow with a recurrence interval of 10 years (7Q10) is shown on the graphs.